This invention relates to devices which create and transmit biological waveforms. More particularly, it relates to such devices that produce simulated electrocardiogram and blood pressure wave-forms.
An electrocardiograph is an instrument used to diagnose disorders of the heart. It detects and records the electrical impulse developed by the heart with each beat. A recording of the impulse is called an electrocardiogram, often abbreviated EKG.
To make a recording, electrical impulses from the heart are gathered from a plurality of points. Most commonly, electrodes, which are attached to wires from the electrocardiograph, are placed on a patient's right arm (RA), left arm (LA) and right leg (RL), the right arm or left arm electrodes being commonly used in conjuction with the RL electrode to sense the patient's respiration rate.
Impulses from a normal heart make records of a specific size and shape. In certain abnormal conditions, the recording shows changes in this pattern. A normal heart produces an impulse (herein, also called a rhythm) which is periodically and uniformly repeated, but an abnormal heartbeat will produce rhythms which are both normal and abnormal. The abnormal rhythms are known as arrhythmyias. Arrhythmias can be continuous or occur in combination with other rhythms.
These combined arrhythymias can be divided into four groups: (1) bigem, (2) trigem, (3) v/min, and (4) run/v. "Bigem" is short for "bigemini" which describes an impulse pattern comprised of one normal rhythm (herein, also called a primary rhythm) followed by an abnormal rhythm (herein, also called a secondary rhythm), the pattern being periodically repeated. "Trigem" is short for "trigemini" which describes an impulse pattern comprised of two normal rhythms followed by an abnormal rhythm, the pattern being periodically repeated. "V/min" is short for "ventrical premature beats per minute" which generally describes an impulse pattern comprised of uniformly repeating rhythms, but with some of the primary rhythms replaced by secondary rhythms, the secondary rhythms never occuring two or more in a row. "Run/v" is short for "run per ventrical premature beats" which generally describes an impulse pattern comprised of uniformly repeating primary rhythms, but with a primary rhythm being occasionally replaced by a run (one or more in a row) of secondary rhythms.
There exist devices which are used to monitor a patient's heartbeat, respiration, and blood pressure, and which are adapted to recognize normal and abnormal rhythms. They are commonly referred to as "computerized arrhythmyia systems." In many situations the life of a patient can depend on the ability of these systems to recognize dangerous arrhythmias and to sound an alarm in response thereto. Therefore the calibration and testing of these systems is very important.
This invention presents a means of testing and calibrating these systems. It simulates a patient in that this invention can be connected to an arrhythmyia system and produce impulses which simulate a wide variety of heartbeat patterns. This invention also produces signals which simulate the blood pressure and respiration patterns of a patient. It is capable of completely testing the recognition ability and responses of a conventional arrhthmyia system.
Other advantages and attributes of this invention will be readily discernible upon a reading of the text hereinafter.